A new SiC/SOI-based PWM generator for SiC-based power converters in high temperature environments

A novel SiC/SOI-based PWM gate driver is proposed and designed using current source technique to accomplish variable duty-cycle PWM generation. The ring oscillator and constant current source stages use low power normally-on, epitaxial SiC-JFETs fabricated at Newcastle University. The amplification and control stages use enhancement-mode signal SOI MOSFETs. In the proposed design, the duty cycle can be varied from 10% to 90%. The PWM generator is then evaluated in a 200 kHz step-up converter which results in a 91% efficiency at 81% duty cycle.